Electrical switches

ABSTRACT

An electrical switch includes a pair of fixed contacts, an operating member movable relative to the fixed contacts, and a pair of movable contacts carried by the operating member and engageable with the fixed contacts respectively in an operative position of the switch, one of said four contacts being capable of movement when engaged by its respective mating contact and being arranged to be engaged by its respective mating contact fractionally before the remaining pair of contacts mate, so that both movable contacts can be engaged with their respective fixed contacts in the operative position of the switch.

United States Patent Leighton I541 ELECTRICAL SWITCHES [72] inventor: Peter Watson Leighton, Bumley, England [73] Assignee: Joseph Lucas (industries) Limited, Birmingham, England [22] Filed: July 15,1970

[21] Appl.No.: 55,024

[30] Foreign Application Priority Data Aug. 11, 1969 Great Britain ..40,008/69 [52] U.S.Cl ..200/159 R, 200/16 R [5 l Int. Cl. ..H0lh 3/12 [58] Field oISearch ..200/l59 R, 159 A, 16R, 16A,-

[5 6] Reierences Cited UNITED STATES PATENTS 3,448,226 6/1969 Mading et a1. ..200/l6 R 1151 3,655,933 1451 Apr. 11,1972

3,192,329 6/1965 Murrle ..200/l6A 3,015,001 12/1961 Woofter ..200/l6R Pn'mary Examiner-J. V. Truhe Assistant Examiner-Gale R. Peterson Attorney-Holman & Stern [57] ABSTRACT An electrical switch includes a pair of fixed contacts, an operating member movable relative to the fixed contacts, and a pair of movable contacts carried by the operating member and engageable with the fixed contacts respectively in an operative position of the switch, one of said four contacts being capable of movement when engaged by its respective mating contact and being arranged to be engaged by its respective mating contact fractionally before the remaining pair of contacts mate, so that both movable contacts can be engaged with their respective fixed contacts in the operative position of the switch.

4 Claims, 1 Drawing Figure Patehted A ril 11, 1972 3,655,933

INVENTOR ATT'QRNEYS This invention relates to electrical switches.

A switch according to the invention includes a pair of fixed contacts, an operating member movable relative to the fixed contacts, and a pair of movable contacts carried by the operating member and engageable with the fixed contacts respectively in an operative position of the switch, one of said four contacts being capable of movement when engaged by its respective mating contact and being arranged to be engaged by its respective mating contact fractionally before the remaining pair of contacts mate, so. that both movable contacts can be engaged with their respective fixed contacts in said operative position.

It will be appreciated that in a switch having a pair of rigidly mounted fixed contacts and a pair of movable contacts rigidly mounted on the same operating member manufacturing tolerances could result in one of the movable contacts engaging its respective fixed contact prior to the other movable contact engaging its respective fixed contact whereupon the operating member would be arrested in a position with said other movable contact spaced from its respective fixed contact. The present invention overcomes this problem.

The accompanying drawing is a sectional view of a switch constructed in accordance with one example of the invention.

Referring to the drawing, the switch includes a U-shaped sheet metal frame 11, one limb 12 of which has a metal mounting bracket 13 welded thereto. The other limb 14 of the frame 11 carries a molded synthetic resin member 15, and secured to the member 15 by means of a conductive rivet 16 is a blade terminal 17. The rivet 16 serves to secure the member 15 to the limb 14, and one head 18 of the rivet 16 abuts against the terminal 17 and constitutes an electrical contact.

The limbs 12, 14 of the frame 11, the bracket 13, and the member 15 are formed with axially aligned holes, within which is slidably mounted a synthetic resin spindle 19. One end 21 of the spindle 19 projects from the face of the limb 14 remote from the limb 12 and secured to the end 21 of the spindle 19 by means of a screw 22 is a synthetic resin sleeve 23. The end of the sleeve 23 remote from the spindle 19 is formed with a radially extending shoulder 24, and trapped against the shoulder 24 by the head of the screw 22 is the blade terminal 25. Integral with the blade terminal 25 and extending towards the limb 14 of the frame 11 is a contact 26, and welded to the limb 14 adjacent the contact 26 is a contact 27. At its end adjacent the spindle 19 the sleeve 23 is formed with an integral, outwardly extending peripheral flange 28, the face of which remote from the spindle 19 is chamfered so that the thickness of the flange 28 decreases towards its periphery. Nonrotatably mounted on the sleeve 23 between the flange 28 and the terminal 25 is a further blade terminal 29, the blade terminal 29 being spaced from the blade terminal 25 by an insulating washer 31. Both the terminal 25 and the terminal 29 are held against axial and rotational movement relative to the sleeve 23, but by virture of the chamfered face of the flange 28, there is sufficient clearance between the flange 28 and the terminal 29 to permit the terminal 29 to pivot on the sleeve 23 in a direction towards and away from the head 18 of the rivet 16. A compression spring 32 is secured at one end to the spindle 19, and bears at its other end against the member 15, the spring 32urging the spindle 19 in a direction to engage the contact 26 with the contact 27, and to engage a contact area of the terminal 29 with the contact defined by the head 18 of the rivet 16, thereby completing a first electrical circuit between the terminal 25 and the frame 11, and a second electrical circuit between the terminals 17,29.

Owing to manufacturing tolerances involved in the production of the switch described above, it is extremely difficult to ensure that both circuits are made simultaneously. For this reason the switch is so arranged that the terminal 29 engages the head 18 fractionally before the contact 26 engages the contact 27. Since the plate 29 is capable of a small degree of pivotal movement relative to the sleeve 23, then the movement of thespindle 19 will not be arrested by the en a ement of the terminal 29 with the head 18, and the spindfe9 can move further under the action of the spring 32 to engage the contact 26 with the contact 27. it will be appreciated, that had the switch been constructed with the terminal 29 rigidly secured to the spindle 19, then had the terminal 29 engaged the head 18 prior to the engagement of the contact 27 by the contact 26, the spindle 19 will have been arrested, and the contact 27 would not have been engaged by the contact 26.

The switch is intended for use in a road vehicle, and is intended to be operated by a door of the road vehicle. In such a construction the switch is secured within the bodywork of the vehicle, by means of the bracket 13, with the end of the spindle 19 remote from the screw 22 pro'ecting through the door frame of the vehicle so as to be engageable by the door when the door is in its closed position. When the door of the vehicle is closed, the spindle 19 is held in a position wherein neither of the circuits of the switch is made, and upon opening the door the spindle 19 is moved by the spring 32 to close both circuits. The contact 27 is of course earthed, through the frame 11 and the bracket 13, and the contacts 26, 27 can be used to control for example, a courtesy light of the vehicle, while the contacts constituted by the head 18 and the terminal 29, for example, be connected in a warning circuit including a warning devide and a switch operated by insertion of the ignition key into the ignition switch of the vehicle, so that a warning will be given to the driver of the vehicle if the door is opened while the ignition key is still in the ignition switch.

If desired, the frame 11 can be insulated from the body of the vehicle, and a further blade terminal can be provided, the further blade terminal being electrically connected to the contact 27, so that both of the circuits of the switch are insulated return circuits.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. An electrical switch including a pair of fixed contacts, an operating member movable relative to the fixed contacts, and a pair of movable contacts carried by the operating member and engageable with the fixed contacts respectively in an operative position of the switch, one of said four contacts being capable of movement when engaged by its respective mating contact, and being arranged to be engaged by its respective mating contact fractionally before the remaining pair of contacts mate, so that both movable contacts can be engaged with their respective fixed contacts in said operative position.

2. A switch as claimed in claim 1 wherein said operating member is resiliently urged to said operative position.

3. A switch as claimed in claim 1 wherein one of said pair of movable contacts is mounted on an insulating sleeve carried by the operating member, said sleeve being formed adjacent said one movable contact with an integral flange and the face of said flange presented to said one movable contact being chamfered so that the thickness of the flange decreases towards the periphery thereof and so that said one movable contact is capable of pivotal movement relative to the sleeve when engaged by its respective fixed contact.

4. A switch as claimed in claim 3 wherein said pair of fixed contacts are mounted on a conductive framework with the fixed contact which engages said one movable contact in use being carried by an insulating member, said insulating member serving to mount the contact on the framework and to insulate the contact from the framework. 

1. An electrical switch including a pair of fixed contacts, an operating member movable relative to the fixed contacts, and a pair of movable contacts carried by the operating member and engageable with the fixed contacts respectively in an operative position of the switch, one of said four contacts being capable of movement when engaged by its respective mating contact, and being arranged to be engaged by its respective mating contact fractionally before the remaining pair of contacts mate, so that both movable contacts can be engaged with their respective fixed contacts in said operaTive position.
 2. A switch as claimed in claim 1 wherein said operating member is resiliently urged to said operative position.
 3. A switch as claimed in claim 1 wherein one of said pair of movable contacts is mounted on an insulating sleeve carried by the operating member, said sleeve being formed adjacent said one movable contact with an integral flange and the face of said flange presented to said one movable contact being chamfered so that the thickness of the flange decreases towards the periphery thereof and so that said one movable contact is capable of pivotal movement relative to the sleeve when engaged by its respective fixed contact.
 4. A switch as claimed in claim 3 wherein said pair of fixed contacts are mounted on a conductive framework with the fixed contact which engages said one movable contact in use being carried by an insulating member, said insulating member serving to mount the contact on the framework and to insulate the contact from the framework. 